Re: JPEG's
Re: JPEG's
- Subject: Re: JPEG's
- From: Stephen Clark <email@hidden>
- Date: Wed, 3 Jul 2002 06:48:52 -0500
On Tuesday, July 2, 2002, at 11:49 PM, Anthony Sanna wrote:
I read in one of the posts that it's best to save digital camera files
as
"raw" and not .jpg...
True enough, if your camera allows that capability.
...because every time the file is resaved as a .jpg,
more information is lost. I don't have a digital camera, but began
wondering about multiple .jpg saves. Is .jpg max-quality 12 lossless,
or
will multiple saves at 12 still result in image degradation?
I believe yes: take a small image, save thru multiple iterations @
jpg12, then open two of these versions at random & open, do an Image /
Mode / Calculations set for Difference and New Document between the same
color channel of each image. Check the Histogram of the resulting file,
or go to Levels & set Input to 0 - 1.00 - 10. Lossless would imply that
the result,
no matter how many times the file were re-saved at 12, would still yield
only one value.
THEN go to <
http://www.fnordware.com/> & check out the Photoshop plug-in
for JPEG2000 which, as this page touts: "is a free plug-in for reading
and writing the JPEG 2000 file format, the successor to JPEG. Also known
as JP2, JPEG 2000 uses wavelet compression to create small images with
less objectionable artifacts than JPEG's DCT compression. It also
features: Alpha transparency, Lossless compression mode,16-bit color.
Read the Release Notes for more information."
I ran across it last week; works fine for me in Photoshop 7 running on
10.1.5.
Hope this helps.
Steve Clark
Chicago
_______________________________________________
colorsync-users mailing list | email@hidden
Help/Unsubscribe/Archives:
http://www.lists.apple.com/mailman/listinfo/colorsync-users
Do not post admin requests to the list. They will be ignored.